Part 5: Immunity and Vaccinations

Question 1

State the function of antibodies.

Answer 1

Chemically lock onto antigens

Question 2

Where are lymphocytes produced?

Answer 2

In the bone marrow

Question 3

Name a key features of lymphocytes.

Answer 3

They have a nucleus

Question 4

Name the functions of lymphocytes. (2)

Answer 4

1. Release histamine when the body is hurt.
2. Release antibodies

Question 5

Are lymphocytes a specific or non-specific immune response?

Answer 5

Specific

Question 6

Are phagocytes a specific or non-specific immune response?

Answer 6

Non-specific

Question 7

State the functions of phagocytes. (3)

Answer 7

1. Move through the capillary wall to the blood vessel.
2. Engulf, kill and digest any microorganism that does not fit
3. Patrol the body

Question 8

Describe the function of memory cells. (3)

Answer 8

1. When the body selects the correct type of lymphocyte to fight against the invading pathogen,
2. Memory cells are produced,
3. Which makes the immune system faster is the same pathogen enters the immune system again.

Question 9

What is the primary immune response?

Answer 9

The first time the immune system encounters a pathogen

Question 10

What is the secondary immune response?

Answer 10

The second or subsequent time the immune system encounters a pathogen.

Question 11

When bacteria infect the body, they often release toxins- explain how the body deals with these toxins. (4)

Answer 11

1. Lymphocytes produce antibodies that are a specific shape
2. Antibodies bind to toxins as they are complementary shapes
3. Phagocytes engulf the toxin-antitoxin complex by phagocytocis.
4. Toxins are then destroyed by phagocytes.

Question 12

Compare the differences between the primary and secondary immune response. (4)

Answer 12

1. Shorter delay before antibody concentration increases in secondary immune response than in primary immune response.
2. The rate of increase of antibodies is greater in secondary immune response than in primary immune response.
3. The maximum antibody concentration is higher in secondary immune response than primary immune response.
4. In secondary immune response, the antibody concentration remains higher for longer afterwards than primary immune response.

Question 13

Suggest and explain a reason for differences between primary and secondary immune response. (3)

Answer 13

1. Memory cells mean that lymphocytes’ numbers increase faster
2. Less delay in recognising the pathogen
3. Therefore, antibody production is faster, and more are produced.

Question 14

Define ‘vaccination’. (2)

Answer 14

1. Vaccinations consist of an injection of a weakened or dead pathogen.
2. They provide immunity against a specific disease for different periods of time depending on the vaccination.

Question 15

Explain how vaccination occurs. (4)

Answer 15

1. Weakened pathogen is injected in person.
2. Antibodies are produced by lymphocytes to destroy pathogens.
3. The vaccinated person is now exposed to the pathogen.
4. The vaccinated person doesn’t get ill as the memory cells make antibodies to kill the pathogens.

Question 16

Explain why the cowpox virus gave James Phipps immunity to smallpox. (6)

Answer 16

1. Edward Jenner realised that milkmaids didn’t catch smallpox. They caught cowpox, which gave them spots, but didn’t kill them.
2. He took pus from a cowpox spot of milkmaid Sarah Nelmes.
3. He injected the pus into a boy called James Phipps.
4. The boy caught cowpox but got better.
5. Jenner then took pus from a smallpox and injected it into the boy. This was very risky as the boy could have died.
6. The boy’s immune system recognised the smallpox virus and destroyed it. He did not become ill.

Question 17

Describe the relationship between the percentage of people being vaccinated and the number of reported cases.

Answer 17

When the percentage of people vaccinated decreases, the number of reported cases increases.

Question 18

Define ‘herd immunity’